GT5 run in 1080p so the answer is yes. I haven't read anything about GT5 not in 1080p. While GT5 will run in 1080p it will not be in 16:9 format but 5:4 like my old PC monitor. Racing games like Gt5 will clearly benefit run in 1080p since you are looking in the distance (down the road) most of the time. It's more useful to have 1080 lines vertical then to have 1920 pixels running across.
By the way I haven't seen a HD movie yet that runs in 16:9 format. Some runs in 2:1 format.